Familial breast cancer predisposition due to a germline mutation in either BRCA1 or BRCA2 genes is an autosomal dominant condition.

This risk management guideline has been developed for individuals who have NOT been diagnosed with a relevant cancer/tumour. The care of affected individuals should be individualised based on their clinical situation, and the monitoring they need as part of their treatment and post-treatment follow up.

Breast cancer

No trials have evaluated whether manual palpation is effective but mammography not useful. Other factors such as obesity, chest wall radiation and gynaecomastia can increase the risk of male breast cancer.r BRCA related (especially BRCA2) male breast cancer is known to be more aggressive and have a more unfavourable prognosis than those occurring in individuals without a BRCA gene mutation.r

Prostate cancer

In the general population surveillance can be associated with over-diagnosis and over treatment with no evidence for improved short term survival (ten year period). There is preliminary evidence for value in surveillance of men with BRCA mutations,rr as data suggests that BRCA-related prostate cancer is aggressive and occurs at a younger age than sporadic prostate cancer.rr

Pancreatic cancer

There is currently no effective surveillance that detects early pancreatic cancer.

First degree (blood) relatives (parents/brothers/sisters/children) are at 50% risk of having inherited the BRCA1 or BRCA2 mutation. First degree relatives should be referred to a local family cancer clinic.

Bibliography

The risks of cancers other than breast and ovarian amongst BRCA1 and BRCA2 mutation carriers are based on relatively few family based studies with the risk of specific cancers tested in population based samples of cancers from founder populations. We assessed risks of other cancers in 268 BRCA1 families and 222 BRCA2 families using a person years at risk analysis from 1975 to 2005. Cancer confirmations were overall higher than in previous family based studies at 64%. There was no overall increase in risk for BRCA1 carriers although oesophagus had a significant increased RR of 2.9 (95% CI 1.1-6.0) and stomach at 2.4 (95% CI 1.2-4.3), these were based mainly on unconfirmed cases. For BRCA2 increased risks for cancers of the pancreas (RR 4.1, 95% CI 1.9-7.8) and prostate (RR 6.3, 95% CI 4.3-9.0) and uveal melanoma (RR 99.4, 95% CI 11.1-359.8) were confirmed. Possible new associations with oesophagus (RR 4.1, 95% CI 1.9-7.8) and stomach (RR 2.7, 95% CI 1.3-4.8) were detected but these findings should be treated with caution due to lower confirmation rates. In contrast to previous research a higher risk of prostate cancer was found in males with mutations in the BRCA2 OCCR region. The present study strengthens the known links between BRCA2 and pancreatic and prostate cancer, but throws further doubt onto any association with BRCA1. New associations with upper gastro-intestinal malignancy need to be treated with caution and confirmed by large prospective studies.

The information contained in this document is based on the highest level of available evidence and consensus of the eviQ reference committee regarding their views of currently accepted approaches to care or treatment. Any clinician seeking to apply or consult this document is expected to use independent clinical judgement in the context of individual clinical circumstances to determine any patient's care or treatment. Use is subject to eviQ’s disclaimer available at www.eviQ.org.au